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u-boot/arch/x86/lib/string.c
Tom Rini 83d290c56f SPDX: Convert all of our single license tags to Linux Kernel style
When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from.  So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry.  Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.

In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.

This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents.  There's also a few places where I found we did not have a tag
and have introduced one.

Signed-off-by: Tom Rini <trini@konsulko.com>
2018-05-07 09:34:12 -04:00

292 lines
6.5 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 1991,1992,1993,1997,1998,2003, 2005 Free Software Foundation, Inc.
* This file is part of the GNU C Library.
* Copyright (c) 2011 The Chromium OS Authors.
*/
/* From glibc-2.14, sysdeps/i386/memset.c */
#include <linux/types.h>
#include <linux/compiler.h>
#include <asm/string.h>
typedef uint32_t op_t;
void *memset(void *dstpp, int c, size_t len)
{
int d0;
unsigned long int dstp = (unsigned long int) dstpp;
/* This explicit register allocation improves code very much indeed. */
register op_t x asm("ax");
x = (unsigned char) c;
/* Clear the direction flag, so filling will move forward. */
asm volatile("cld");
/* This threshold value is optimal. */
if (len >= 12) {
/* Fill X with four copies of the char we want to fill with. */
x |= (x << 8);
x |= (x << 16);
/* Adjust LEN for the bytes handled in the first loop. */
len -= (-dstp) % sizeof(op_t);
/*
* There are at least some bytes to set. No need to test for
* LEN == 0 in this alignment loop.
*/
/* Fill bytes until DSTP is aligned on a longword boundary. */
asm volatile(
"rep\n"
"stosb" /* %0, %2, %3 */ :
"=D" (dstp), "=c" (d0) :
"0" (dstp), "1" ((-dstp) % sizeof(op_t)), "a" (x) :
"memory");
/* Fill longwords. */
asm volatile(
"rep\n"
"stosl" /* %0, %2, %3 */ :
"=D" (dstp), "=c" (d0) :
"0" (dstp), "1" (len / sizeof(op_t)), "a" (x) :
"memory");
len %= sizeof(op_t);
}
/* Write the last few bytes. */
asm volatile(
"rep\n"
"stosb" /* %0, %2, %3 */ :
"=D" (dstp), "=c" (d0) :
"0" (dstp), "1" (len), "a" (x) :
"memory");
return dstpp;
}
#define OP_T_THRES 8
#define OPSIZ (sizeof(op_t))
#define BYTE_COPY_FWD(dst_bp, src_bp, nbytes) \
do { \
int __d0; \
asm volatile( \
/* Clear the direction flag, so copying goes forward. */ \
"cld\n" \
/* Copy bytes. */ \
"rep\n" \
"movsb" : \
"=D" (dst_bp), "=S" (src_bp), "=c" (__d0) : \
"0" (dst_bp), "1" (src_bp), "2" (nbytes) : \
"memory"); \
} while (0)
#define WORD_COPY_FWD(dst_bp, src_bp, nbytes_left, nbytes) \
do { \
int __d0; \
asm volatile( \
/* Clear the direction flag, so copying goes forward. */ \
"cld\n" \
/* Copy longwords. */ \
"rep\n" \
"movsl" : \
"=D" (dst_bp), "=S" (src_bp), "=c" (__d0) : \
"0" (dst_bp), "1" (src_bp), "2" ((nbytes) / 4) : \
"memory"); \
(nbytes_left) = (nbytes) % 4; \
} while (0)
void *memcpy(void *dstpp, const void *srcpp, size_t len)
{
unsigned long int dstp = (long int)dstpp;
unsigned long int srcp = (long int)srcpp;
/* Copy from the beginning to the end. */
/* If there not too few bytes to copy, use word copy. */
if (len >= OP_T_THRES) {
/* Copy just a few bytes to make DSTP aligned. */
len -= (-dstp) % OPSIZ;
BYTE_COPY_FWD(dstp, srcp, (-dstp) % OPSIZ);
/* Copy from SRCP to DSTP taking advantage of the known
* alignment of DSTP. Number of bytes remaining is put
* in the third argument, i.e. in LEN. This number may
* vary from machine to machine.
*/
WORD_COPY_FWD(dstp, srcp, len, len);
/* Fall out and copy the tail. */
}
/* There are just a few bytes to copy. Use byte memory operations. */
BYTE_COPY_FWD(dstp, srcp, len);
return dstpp;
}
void *memmove(void *dest, const void *src, size_t n)
{
int d0, d1, d2, d3, d4, d5;
char *ret = dest;
__asm__ __volatile__(
/* Handle more 16 bytes in loop */
"cmp $0x10, %0\n\t"
"jb 1f\n\t"
/* Decide forward/backward copy mode */
"cmp %2, %1\n\t"
"jb 2f\n\t"
/*
* movs instruction have many startup latency
* so we handle small size by general register.
*/
"cmp $680, %0\n\t"
"jb 3f\n\t"
/* movs instruction is only good for aligned case */
"mov %1, %3\n\t"
"xor %2, %3\n\t"
"and $0xff, %3\n\t"
"jz 4f\n\t"
"3:\n\t"
"sub $0x10, %0\n\t"
/* We gobble 16 bytes forward in each loop */
"3:\n\t"
"sub $0x10, %0\n\t"
"mov 0*4(%1), %3\n\t"
"mov 1*4(%1), %4\n\t"
"mov %3, 0*4(%2)\n\t"
"mov %4, 1*4(%2)\n\t"
"mov 2*4(%1), %3\n\t"
"mov 3*4(%1), %4\n\t"
"mov %3, 2*4(%2)\n\t"
"mov %4, 3*4(%2)\n\t"
"lea 0x10(%1), %1\n\t"
"lea 0x10(%2), %2\n\t"
"jae 3b\n\t"
"add $0x10, %0\n\t"
"jmp 1f\n\t"
/* Handle data forward by movs */
".p2align 4\n\t"
"4:\n\t"
"mov -4(%1, %0), %3\n\t"
"lea -4(%2, %0), %4\n\t"
"shr $2, %0\n\t"
"rep movsl\n\t"
"mov %3, (%4)\n\t"
"jmp 11f\n\t"
/* Handle data backward by movs */
".p2align 4\n\t"
"6:\n\t"
"mov (%1), %3\n\t"
"mov %2, %4\n\t"
"lea -4(%1, %0), %1\n\t"
"lea -4(%2, %0), %2\n\t"
"shr $2, %0\n\t"
"std\n\t"
"rep movsl\n\t"
"mov %3,(%4)\n\t"
"cld\n\t"
"jmp 11f\n\t"
/* Start to prepare for backward copy */
".p2align 4\n\t"
"2:\n\t"
"cmp $680, %0\n\t"
"jb 5f\n\t"
"mov %1, %3\n\t"
"xor %2, %3\n\t"
"and $0xff, %3\n\t"
"jz 6b\n\t"
/* Calculate copy position to tail */
"5:\n\t"
"add %0, %1\n\t"
"add %0, %2\n\t"
"sub $0x10, %0\n\t"
/* We gobble 16 bytes backward in each loop */
"7:\n\t"
"sub $0x10, %0\n\t"
"mov -1*4(%1), %3\n\t"
"mov -2*4(%1), %4\n\t"
"mov %3, -1*4(%2)\n\t"
"mov %4, -2*4(%2)\n\t"
"mov -3*4(%1), %3\n\t"
"mov -4*4(%1), %4\n\t"
"mov %3, -3*4(%2)\n\t"
"mov %4, -4*4(%2)\n\t"
"lea -0x10(%1), %1\n\t"
"lea -0x10(%2), %2\n\t"
"jae 7b\n\t"
/* Calculate copy position to head */
"add $0x10, %0\n\t"
"sub %0, %1\n\t"
"sub %0, %2\n\t"
/* Move data from 8 bytes to 15 bytes */
".p2align 4\n\t"
"1:\n\t"
"cmp $8, %0\n\t"
"jb 8f\n\t"
"mov 0*4(%1), %3\n\t"
"mov 1*4(%1), %4\n\t"
"mov -2*4(%1, %0), %5\n\t"
"mov -1*4(%1, %0), %1\n\t"
"mov %3, 0*4(%2)\n\t"
"mov %4, 1*4(%2)\n\t"
"mov %5, -2*4(%2, %0)\n\t"
"mov %1, -1*4(%2, %0)\n\t"
"jmp 11f\n\t"
/* Move data from 4 bytes to 7 bytes */
".p2align 4\n\t"
"8:\n\t"
"cmp $4, %0\n\t"
"jb 9f\n\t"
"mov 0*4(%1), %3\n\t"
"mov -1*4(%1, %0), %4\n\t"
"mov %3, 0*4(%2)\n\t"
"mov %4, -1*4(%2, %0)\n\t"
"jmp 11f\n\t"
/* Move data from 2 bytes to 3 bytes */
".p2align 4\n\t"
"9:\n\t"
"cmp $2, %0\n\t"
"jb 10f\n\t"
"movw 0*2(%1), %%dx\n\t"
"movw -1*2(%1, %0), %%bx\n\t"
"movw %%dx, 0*2(%2)\n\t"
"movw %%bx, -1*2(%2, %0)\n\t"
"jmp 11f\n\t"
/* Move data for 1 byte */
".p2align 4\n\t"
"10:\n\t"
"cmp $1, %0\n\t"
"jb 11f\n\t"
"movb (%1), %%cl\n\t"
"movb %%cl, (%2)\n\t"
".p2align 4\n\t"
"11:"
: "=&c" (d0), "=&S" (d1), "=&D" (d2),
"=r" (d3), "=r" (d4), "=r"(d5)
: "0" (n),
"1" (src),
"2" (dest)
: "memory");
return ret;
}